These 9 military actions changed America . . . and the world

Had the Confederates won the Battle of Gettysburg, it's possible that there would have been another Union victory down the road and the war would've ended the same way . . . but who knows? The fact is, Gettysburg turned the tide of the Civil War, gave Lincoln an opportunity to end slavery, and kept the country together. It's safe to say the world would have turned into a vastly different place had there been two separate Americas.

Several times in history, the American military has taken action had huge ripple effects across the planet, sometimes immediately, sometimes decades later. Here are 9 examples:

1. Valley Forge

Historians point to Saratoga as the big turning point in the Revolution because it not only wiped out Burgoyne's Army in the north but convinced the French that maybe those American peasants had a chance after all. Still stinging from their defeat in the French and Indian War ten years earlier, France's King Louis XVI threw was all too eager to crash the North American party and make the American Revolution a global fight so the American Army entered its winter camp outside Philadelphia on a winner's high.

But that soon changed. Undersupplied, tired, frozen, and starving, the Continental Army was on the verge of breaking every day for several long months in the winter of 1777-1778. It was the first time American perseverance to be free was put to the test and had the Colonials broken and run, there might not be an America at all. At Valley Forge, the bonds with the French were greatly strengthened, Von Stueben's drill was perfected (making the Continental's a real Army), and Washington, whom some wanted to replace with Horatio Gates, survived to go on to be the father of the greatest country ever.

2. The Battle of New Orleans

Andrew Jackson's beat-down of the British in 1815 wasn't the biggest battle of that war, but it kicked the last European invaders out of North America for good and propelled Jackson to the White House to be President for eight years. Jackson expanded the powers of the Presidency, made trade agreements with several European countries, opened trade agreements with Asia, and founded the modern Democratic Party. But his actions also led directly to the forced removal and relocation of nearly 50,000 Native Americans from the South to the Midwest on the Trail of Tears. None of that would have happened without his success at the Battle of New Orleans.

3. Winfield Scott's March to Mexico City

It wasn't much of a military action, but General Winfield Scott marched into Mexico City in 1848 to end the Mexican War and effectively made Texas and California US territories. Imagine what the USA would look like today if those two giant states were still part of Mexico. But those acquisitions also had a dark side. President James K. Polk was obsessed with westward expansion and once he had California, he needed routes for settlers to get there, which fueled the flames of slavery and (arguably) set the stage for the Civil War and Indian Wars.

4. The Second Battle of the Marne

WWI was a pivotal moment for the United States because it was the first time the nation deployed soldiers overseas to fight in another country's war. Although America had been involved in power projection during the Spanish-American War, WWI was a whole new ballgame and established the U.S.A. as an international force to be reckoned with. In particular, the Second Battle of the Marne River in France was crucial to the Allied victory. That defeat was the beginning of the end for Germany just 100 days later.

5. The Battle of Midway

In June 1942, the war in the Pacific was supposed to be a "holding effort" while the war in Europe was America's primary focus and demanded most of the nation's resources. But the Japanese had different plans and attacked the U.S. Garrison at Midway Atoll, which ended up being a big mistake. When it was over, four Japanese aircraft carriers had been sunk and a crippling number of aircrews were lost. Japan was unable to mount effective offensive operations after Midway and its domination of the Pacific was on a downward spiral from that point on.

6. Normandy (Operation Overlord)

Invading Europe in 1944 was by far the greatest invasion ever attempted. Failure would have resulted in a Nazi Europe, probably to this day.  You could argue the Battle of the Bulge was just as important, but no military endeavor in the history of the U.S. was so ambitious and critical as the invasion and liberation of Europe. The entire continent (and arguably the world) would not look anything like it does today if the Allies had failed at Normandy.

7. Hiroshima

America is the only country to ever use a nuclear weapon against another nation. The bomb dropped on Hiroshima from the Enola Gay vaulted the world into the nuclear age and started the Cold War.

8. The Pusan Perimeter

In August 1950, the combined U.S. and U.N. Forces in Korea were backed into a corner by the invading North Korean Army between the cities of Pusan and Taegu. Despite constant attacks, the Pusan Perimeter never collapsed and by September, the Allies were on the offensive while MacArthur was invading at Inchon. If the perimeter had collapsed, it's possible that we still would have prevailed, but who's to say? All that is certain is that the perimeter didn't break and South Korea is today a strong democracy with the ninth largest economy in the world. Imagine Kim Jong Un with twice as much land and resources as he has now.

9. The Invasion of Iraq

It's only been thirteen years since the U.S. invaded Iraq and only time will tell the total effect of that action, but it's safe to say that if Saddam Hussein were still around (even allowing that he wasn't a very nice guy), the American military would be in better shape, AQI and ISIS would never have formed, Iran's influence across the region would be less of a threat, and the domestic political landscape wouldn't be so chaotic.

Kelly Crigger is a retired lieutenant colonel and the author of "Curmudgeonism; A Surly Man's Guide to Midlife."